The present invention relates generally to transmitters and more specifically to a system and method for calibrating transmitter power.
Transmission standards typically limit the total radiated power from a transmitter/antenna system. In a typical transmitter/antenna system, the transmitter output power is controllable and the antenna has a known gain. Thus, to meet transmission standards, the antenna gain and transmitter power are set so that the power limit of the standard is not exceeded when the antenna is directly connected to the transmitter, a best case scenario as it is assumed there is no power loss between the transmitter and the antenna.
However, antennas that are remote from a transmitter may be connected by an arbitrary length of cable that has an unknown loss. Because of the power loss within the cable, the true system radiated power is reduced, resulting in a reduction in transmission system efficiency. Thus a technique is needed to measure the radiated power at the antenna so that cable loss can be calibrated out of the system by increasing the transmit power to make up for the loss.